Silk Purses from Sows’ Ears

Silk Purses from Sows’ Ears

FEATURES

BUILDING CONSTRUCTION

When I was a boy, as my mother would work desperately to make my unruly hair look presentable, my grandmother would give forth with the old country axiom, “You can’t make a silk purse out of a sow’s ear.”

All over the country, old buildings are being restored, rehabilitated, and adapted to other uses. In many cases, a building made to look like a silk purse through one of these processes may be, in reality, a sow’s ear when it comes to fire safety.

Old buildings may be preserved because of undeniably historic value, as part of our architectural heritage, to preserve or rehabilitate a specific neighborhood, or because a developer expects to make a bundle fixing up an old dump into attractive-looking apartments, shops, or offices. Whether construction work is done for one of these lofty purposes or for ordinary renovation, many of the changes create collapse potentials or voids in which hidden fire can develop and grow. These degrade the safety of firefighters, the people who have the unenviable right to go thisaway, into an inferno, when all who can have gone thataway.

Each project is different, and many problems are unique, but I’ll cite here some of the situations I’ve found or learned of. They’re organized into general topical areas, but no ranking of significance is intended. To you, the important items are those that create special fire suppression problems or hazards in your community.

Devotion to authenticity

Shingles. While many restorations—such as the granddaddy of them all, Colonial Williamsburg— have found it possible to use firerated, treated wood shingles or noncombustible shingles that look like wood, some have insisted on authentic wood shingles, thus setting the stage for a genuine, historic-style conflagration.

Inward-swinging doors. The doors of Independence Hall swing inward just as they were built. The National Park Service, as a policy, controls the number of visitors in the building and has trained, fulltime personnel on duty. But other organizations controlling buildings with inward-swinging doors may push as many visitors through as possible, and attendants may be well-meaning, parttime volunteers, trained in the canned patter but ignorant of the disaster potential.

Some such facilities “plan” to have all doors latched open when the building is occupied. One wonders what happens in the wintertime. Why not go through your local historic buildings in civvies, as a tourist. You might get a rude surprise.

Masonry walls

Sand-lime mortar. Most masonry buildings built more than half a century ago were built with watersoluble sand-lime mortar. Federal regulations, which a developer must follow to qualify for desirable tax credits, require that such buildings be repaired with sand-lime mortar because the much harder Portland cement mortar would be detrimental to soft, old bricks.

This tragic collapse in 1976 of a supermarket roof in New York City is just one example of how alteration, rehabilitation, restoration, preservation, and adaptive use can create dangers for the firefighter.

Photo by Robert Carpenter

Examine the bricks when walls built with sand-lime mortar are demolished; there’s little adhesion of the mortar. Water leaks or fire hose streams can literally “unglue” the wall and cause collapse. In the Empire Apartments in Washington, the wall above an opening was supported on a beam cut into the old sand-lime masonry wall. Leaking water washed out the mortar and the structure collapsed, causing several fatalities.

Interior walls. Many old buildings have multiple brick-masonry interior walls. The beam spans are short, and thus spaces are small. To make larger spaces, portions of walls are removed during renovation, leaving the problem of supporting the brick wall above. A beam and a cast iron column supporting but not connected to the beam are often used. In the remodeling of the Vendome Hotel in Boston, an air duct opening was cut through the wall directly below a cast iron column supporting a brick wall, and that weakened the support system. Nine firefighters were killed in the resultant collapse.

In an unsprinklered, heavy-timber and brick factory converted to shops in Washington, the masonry above an opening through an interior bearing wall built of brick is supported by an unprotected steel lintel, which could expand and weaken in the heat of a fire and create a potential for disaster.

The hidden-wall trick. The bearing walls of masonry buildings adjacent to one another, such as stores on a small-town Main Street, have served successfully as fire barriers. But the solid-beam construction used in such buildings permits a space that’s usually only 25 feet wide. So it has long been a practice to unite two or more buildings into one occupancy at ground-floor level by opening existing bearing walls. Some sort of a column and beam arrangement supports the remaining heavy masonry walls above. The columns are often unprotected steel, or cast iron possibly unconnected to the beams. Some beams are wood. Failure of these new support structures will cause the collapse of the brick bearing walls above.

Unsuspected openings. Sometimes stores once connected are later divided. The opening may be closed.up with masonry, but often a closure much weaker (in the face of fire) is used instead.

An unsuspected old basementlevel connection between two buildings that stood at right angles to one another permitted a multiplealarm fire in New York City’s “Hell’s Hundred Acres”—now fashionable, restored Soho—to break out in the exposed building as units were leaving the scene of the fire in the first building.

Wooden lintels and leveling beams. Probably the chief hazard that so-called brick walls pose for firefighters stems from the fact that they’re not entirely of brick. Look at the interior side of a brick wall over any openings. Instead of a brick arch, you’ll often find a wooden lintel. If this burns, the wall above will collapse.

Wood beams were often laid directly into a wall to provide a level base for floor beams. If such a beam burns out, there will be a plane of weakness in the wall, like a score on a sheet of gypsum board. In many remodelings, old plaster is removed to show the brick wall. This is an advantage in that we can see any defects if we take the trouble to look. But it’s also a detriment, because the plaster barrier between the fire and the wooden elements is removed.

Cosmetic patches. Cracks in brick walls usually mean foundation problems, which mav be serious. Pointing the cracks may keep out water and improve the appearance, but it doesn’t cure the basic problem.

Bricks themselves can actually be rotten if they’re of poor quality. Parging or stucco is often used to hide the deteriorated condition that the bricks have fallen into with age.

The bearing walls of the two structures above have been breached to create a single occupancy on the first floor.The mill at below left has been converted into small outlet stores. It's fully sprinklered—except for the combustible wooden stairways at below right.

(Photos by Francis L. Brannigan)

Sprinklers

Partial protection. At Indepenence Hall, the nonpublic areas are reportedly sprinklered. The restored historic areas are not; sprinklers wouldn’t be authentic. Reliance in those areas is placed on detection and manual firefighting.

We can’t say too often that fire detection is not fire protection. The fatuous statement that the fire department is close by ignores the realities of fire service availability and the possibility of some deranged person “making a statement” by tossing a firebomb. If such a disaster should occur, all would agree that the “intrusion” of the sprinklers would have been a small price to pay for the continued existence of the building.

In addition, partial protection such as this—or the isolated sprinklers that building inspection departments often permit in lieu of stairway enclosures—can be a hazard to firefighters. Sprinkler heads away from the fire area can operate, producing water flow in heated atmospheres which isn’t extinguishing any fire. This is called “selective placement” of automatic sprinklers, a fancy term for pure guesswork. The only person who knows where a fire will start is the arsonist.

Partial protection is also a problem in downtown department stores, many of which are located in a number of older buildings tied together. In lieu of fire doors at openings between buildings, a line of sprinklers is sometimes installed. If the building is fully sprinklered, these heads won’t come into play when the fire is elsewhere in the building. If it’s not fully sprinklered, the scalding water is a real possibility.

Similarly, unsprinklered buildings have been joined to sprinklered buildings without the installation of proper fire doors. A fire originating in the unsprinklered area would overwhelm the sprinklers.

In a Pennsylvania city, a number of old mills have been converted to factory outlets. One such mill is apparently fully sprinklered. The wooden stairways are not. They’re cut off from the selling floors by self-closing wire-glass doors, but apparently no consideration was given to the potential for a fire in the stairway itself.

Even after full sprinkler protection is installed, the fire department must be on guard against alterations, temporary structures, and other situations in which sprinkler heads can’t “see” the entire structure. Be aware of the extent to which voids have been left unprotected.

Water supply. Years ago, the primary immediate water supply for sprinklers was delivered from elevated tanks bv simple, reliable gravity. Many gravity tanks have been removed, and reliance has been placed on pumps. The fire department should be fully informed as to the reliability and operation of the pumps, power supply, and controls.

Where life safety is dependent upon sprinklers, the building should be evacuated if the sprinkler protection is impaired. Anything less may leave the municipality open to staggering liability judgments.

Automatic alarms

Beware of enthusiastic support for automatic alarm systems as a substitute for sprinklers. You can quote Pat Phillips, chairman of the National Fire Protection Association Committee on Detection Devices: “Fire detection is not fire protection.” An automatic alarm is simply another way, possibly more reliable than humans, of calling the fire department. Today’s fires can develop into flashover in two minutes. The idea that there’s a 15-minute period in which to gain control of the fire is no longer true, if it ever was.

The two metal ceilings left in place here don't keep fire from spreading to the void—they only prevent firefighters from getting to the fire.

Void spaces

New suspended ceilings. Lowering the ceilings of old buildings is most easily accomplished byconstructing new ceilings. This provides a convenient void for the required new utilities, air ducts, and so on. Firestopping is usually nonexistent. Vertical voids connect the horizontal voids so the building is honeycombed with what amounts to one big, interconnected, nonfirestopped void. When fire struck one old factory in New York City that had been converted into apartments, 16 fullstrength truck companies were required to open up all the voids.

Buildings remodeled over the years may have several ceiling voids. An Orlando building showed two metal ceilings, one below the other.

In a rehabilitated William and Mary College dormitory, sprinklers were installed below a new, suspended ceiling. Fire started in or penetrated the unsprinklered void, where it would have encountered the natural firestop of the original ceiling—except that many holes had been broken into the original ceiling, and in some cases, it had been removed. The building was gutted, despite the operation of the sprinklers.

Flooring much weaker than the rest is often used to cover the opening once a staircase is removed—creating the danger of early collapse.

While shopping in a famous New England department store a few years ago, I noticed that the basement ceiling of the 19th-century building had been cut away at every column, probably for a structural analysis. There was an upward draft into the void. Although the building was fully sprinklered, a fire might well get past the sprinklers and move freely through the unsprinklered void.

(There was another problem with the way this had been done: A semicircular section had been cut from the end of each huge, 24inch-by-24-inch wooden beam to allow it to wrap around the supporting cast iron column and rest on a shelf protruding from the column. Thus only a small amount of wood now rested on the shelf. The 1920 McGraw-Hill Handbook of Building Construction called this “dangerous construction.” I’m convinced it’s the cause of collapse in cast-iron-columned structures, rather than the more poetic, redhot cast iron and cold water theory. The preferred method— which I have never seen—is to top the column with a solid, cast iron “pintle,” or pivot pin, much smaller in diameter than the column, and insert it through the wood, leaving much more wood on the girder.)

On a more recent trip, I noted that the department store building had been rehabilitated. An attractive grid ceiling had been installed, with sprinkler heads showing below it. I could only wonder whether the void above the ceiling is unsprinklered and whether the common practice of leaving holes in the old ceiling was followed. If so, the stage is set for a repeat of the William and Mary disaster.

The original floors in this building are supported by full-dimension joists, the addition by flimsy wooden I beams.

(Photos by Francis L. Brannigan)

Many structures have old, lowdensity, combustible tile ceilings. If the ceiling was installed on furring strips, a dangerous void was created. If the tile is glued up, the presence of the flammable adhesive will accelerate the spread of the fire, as happened in a fatal hospital fire in Hartford, Conn.

Building inspection departments may require that a new, suspended ceiling meet the flamespread requirements of the code, without requiring the removal of the old, dangerous, smoke-producing, high fire-load, high flamespread, persistent-burning fiber tile. Be alert to this problem. Expect heavy fire to burst out of the ceiling.

Such a fire did more than $100,000 damage to a Potomac, Md., drug store. And two firefighters in Wyoming, Mich., lost their lives because of such a fire.

A firefighter in Reading, Penn., lost his life when flashover occurred in a fire-resistive building. It was reported that a combustible tile ceiling was involved.

Many such ceilings have fluorescent fixtures installed on the surface of the tile instead of with a space in between. The fixtures are left in place and translucent plastic panels are placed in the new ceiling below the light fixture. That puts the fixture’s transformer— which, if it short-circuits, will burn hotly—in right next to combustible tiles.

If the building owners refuse to take out the entire ceiling, at least get the ceiling tiles removed from around the fixture. Two recent row store fires in Kensington and Frederick, Md., were both due to fluorescent ballasts igniting combustible tile ceilings.

Study and photograph old buildings being rehabilitated. The process opens up the voids so the basic structure can be seen and hidden defects identified. Those with defects should be marked for defensive operations when fire takes possession of the hidden voids.

Interior reconstruction

Trusses. A tea shop is located on the first floor of a commercial building in Chester, England. To clear the dining area of columns, wooden trusses were erected at the ceiling level to support the floors above. A heavy fire in the dining area might precipitate the collapse of the entire structure.

“Not our response area!” you say. No doubt, but we can learn from experiences there, nevertheless. Inspect some of the “old, reliable, heavy-timber buildings” for wood or steel trusses or steel beams or columns inserted to cope with deterioration or heavy loads.

Stairways. In some downtown store alterations, the upper floors are abandoned. The stairway is removed in order to provide groundfloor room. Often just a sheet of metal is placed over the opening. A District of Columbia firefighter died when he fell through such an opening that was protected only by a thin piece of sheet metal.

When stairways are relocated, the old opening is often closed with floor boards laid on 2-by-4’s. This floor area is much more likely to collapse than the original 2-by-8 or 2-by-10 joists. Several firefighters were injured in a collapse of such a floor patch in midtown New York.

Floors. Do you really know what you’re standing on when you enter a fire building? Renovation may compromise the sturdiness of the floors.

The high-ceilinged ballroom of an old, reinforced concrete hotel in Palm Beach, Fla., was divided into two floors. The new floor was to be supported by steel bar joists. The potential for failure of such a floor during fire exposure is greater than for a concrete floor.

Vacant buildings demand more than routine attention.

A mezzanine was inserted in a high-ceilinged occupancy in Orlando, Fla. The original floors are solid-sawn wood joists. The inserted floor was of flimsier wood truss construction.

Two floors were added to a building with sawn-joisted floors in Bethesda, Md. The new floors and roof are of wooden I beam construction, which is also flimsier than the original construction.

Roofs

Intractably leaking roofs are quite common. One solution is to build a new “rain roof” over the old one. Opening such a roof may not vent the structure. A rain roof played a significant role in the roof collapse of a New York City supermarket in which six firefighters died and dozens more were injured.

A Texas building with a leaky roof was to be enlarged. The new roof was built over the entire structure, old and new. The old roof was simply left in place below.

Roofs on additions are often different from the original, sawn-joist wood construction. Wood or steel trusses and wooden I beams are common.

Construction hazards

Vacant buildings. Baltimore, Philadelphia, Minneapolis, Indianapolis, Montreal, and Lynn, Mass., are some of the cities that have suffered massive downtown fires in old buildings with interior walls of combustible masonry as they were being remodeled for adaptive uses. The buildings are usually wide open; sprinkler systems have been removed and the fire is in possession of the building when firefighters arrive. Multimillion-dollar damages have been sustained by nearby structures. Valuable assets and plans for downtown rehabilitation have gone up in smoke.

The identical problem is presented by huge structures not planned for rehabilitation but simply vacant because of economic changes. Sprinklers are often cut off to prevent freezing, and the structures are an open invitation to arson. Three Detroit firefighters recently died in a spectacular fire in such a building. [See “Detroit’s Fatal Warehouse Fire,” Fire Engineering, June 1987.)

No fire department would leave a leaking gasoline tank truck to its own devices on a downtown street. Vacant buildings may be far more hazardous. They demand more than routine attention. A control system should ensure that a disaster won’t occur. Fire departments should develop a file of videotapes of similar fires elsewhere to impress the politicians with the disaster potential. It’s obvious from the pictures that such fires are beyond the suppression capability of even the strongest fire department. It should be noted that, only days before the fire, the city of Detroit had appropriated more than $300,000 to tear down the building that cost the three firefighters’ lives.

Occupied buildings. At Georgetown University Hospital in Washington, I was appalled to see that a plywood partition separated the maternity ward from a major remodeling project. A peek through an access door showed that the debris-strewn construction job was typical—a disaster waiting to happen.

Recently, Boston and New York suffered major fires in occupied office buildings. The fires were in construction materials and shanties on floors being finished out. In both cases, hundreds of people were above the fire. The Boston building (the Prudential) was unsprinklered. The New York building was “fully sprinklered” except for the unfinished third floor. In the New York case, both stairway doors were open on the fire floor, so both stairways became polluted with smoke. This made the standard procedure of using one stairway for attack, the other for evacuation, impossible. Elevator lobby sprinklers operated, but not directly on the fire. Their discharge created a distressing steam condition and flooded the elevators’ electrical system, placing them out of service. Fortunately, the fire was on the third floor and could be suppressed with an exterior attack.

Several years ago, I was invited on a tour of a sprinklered high-rise in New York. The management was justly proud of its fire protection system. But I noted construction materials and flimsy storage sheds on a lower floor. The sprinklers weren’t yet in “because they go in after the ceiling is finished,” the management said. I pointed out that the worst fire hazard in the building was unsprinklered and that the corporate offices were located directly above the hazard floor. The elevator doors on the construction floor were also not yet installed because the management didn’t want them damaged. Despite its fire protection system, the building demonstrated that any construction work in occupied facilities has a major fire and disaster potential and should be strictly controlled.

Renovation. “Pardon our dust while we renovate.” This sign in a hotel should ring as many alarm bells as a tip that the hotel will be torched. A floor may be shut down and used to store the new furniture. Units responding to what they’re told is “a fire in room 622” may find that they have a furniture warehouse full of sleeping people.

Carpet rolls in the hallway were the fuel of a fatal arson fire in a Ft. Worth, Texas, motel. In Silver Spring and Baltimore County, Md., serious fires occurred in hotels in which discarded mattresses were stacked in hallways awaiting removal. Such mattresses are a target for a disgruntled employee. When an unhappy employee of the Dupont Plaza Hotel in San Juan, Puerto Rico, wanted to set a fire, he found a huge pile of newly delivered, combustible furniture. The result was similar to what would have happened had a gasoline tank truck hit the building.

Loads

Many ornate, former residences are saved from demolition by conversion to commercial occupancy. But the floor load of a furniture store is far greater than that expected in a residence. At the time of a fire, there may be little or no reserve strength left in the building’s structural members.

Office occupancies introduce heavy files and safes. A Silver Spring YMCA was located in a former residence. A safe fell through from the top floor to the basement during a fire.

Fire loads may be huge. One of the most dangerous fires in New York history occurred in a former residence loaded with foam rubber. Balls of fire extended a thousand feet into the air. The fire wrecked several floors of a sprinklered loft building nearby. New York’s traditional good luck saved the day. Because of an ice storm, off-duty personnel had been recalled, and triple crews responded. Engine 23, first due, operated two deck pipes and two handlines and rescued two women from the roof with rope life nets (then carried by all engine companies).

Action

The fire department should be in on the planning of any renovations right from the start. Knock out tire idea that you’re bureaucratic obstructionists. Argue that you’re trying to preserve the project and defend the city from possible liability. Have at your fingertips the stories of serious fires that have occurred elsewhere.

Be prepared for a fight which may be nasty. The chief of a Rhode Island fire department was fired by the city manager; he had refused to describe a three-story school building being rehabilitated into apartments for the elderly as a two-story building so sprinklers wouldn’t be required.

Many city officials support a “good fire prevention program,” by which they mean handing out pamphlets to citizens at shopping malls. But fire prevention efforts should be aggressive. Fry for onthe-spot cooperation, but document every item noted.

Suppression forces should preplan realistically for massive defensive operations. Preplans may require frequent updating as conditions change.

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